The invention relates to a sorting installation for letters and large letters and to a method of sorting letters and large letters.
The present invention is suitable, in particular, for sorting large letters and letters into a common mail-delivery sequence. The term “mail-delivery sequence” is understood as meaning a sequence of letters and large letters which corresponds to the sequence in which the mail is delivered by the mailman during his delivery round. For this purpose, the letters and large letters, which are referred to jointly as items of mail hereinbelow, are sorted and arranged such that the first address stop is followed by the second address stop, which is followed by the third address stop, etc.
Up until now, the letters are arranged in the desired mail-delivery sequence in a number of sorting cycles in sorting installations for letters, for example a DBS installation (delivery barcode sorter), which is not suitable for sorting large letters. In addition, large letters are sorted on an interim basis in a sorting installation for large letters, for example an FSS installation (flat sorting system), and are then arranged manually in the desired mail-delivery sequence. It is obvious here that the operation of sorting large letters manually into the desired mail-delivery sequence is time-consuming and costly. The large letters are then added manually, by the mail man, to the letters which have already been arranged in the mail-delivery sequence, this operation also being referred to as collation or merging. This operation is also time-consuming and costly. Collation and sorting into a mail-delivery sequence take place over a number of successive time windows. A large amount of time is thus required overall. In addition it is not possible to use such an installation to sort letters and large letters jointly into a mail-delivery sequence.
As an alternative, it is possible, in a sorting installation, to provide an end location for each destination address, also referred to as delivery point or dispatch address. In a sorting cycle, over a large time window, all the large letters and letters with a certain destination address are sorted into that end location which has been assigned to this destination address. This operation is repeated for all the destination addresses until all the large letters and letters are assigned to the respective end locations. The end locations, finally, are emptied such that the destination addresses are in the order of the mail-delivery sequence. This solution, however, has the disadvantage that, for sorting the letters and large letters into a mail-delivery sequence, an end location is necessary for each destination address. This means that the number of end locations cannot be smaller than the number of destination addresses.
A further possibility is for separate streams of large letters and letters which have already been sorted into a mail-delivery sequence to be arranged in a joint mail-delivery sequence by means of a merger, that is to say an arrangement for bringing the letters and large letters together. An additional sorting cycle and/or an additional time window and, if appropriate, an additional sorting installation for implementing this sorting cycle are necessary here.
From the prior art, EP 0 820 818 A1 has disclosed an apparatus which is intended for sorting letters into a certain sequence and utilizes an interim store. The interim store comprises storage pockets which circulate in a conveying loop, with two semicircular conveying sections, on a conveying arrangement and can each receive an item of mail and discharge the same, on command, into the actual set-down containers. In the first instance here, all of the items of mail which are to be ordered are accommodated in any desired sequence in the storage pockets of the interim store. The items of mail are then removed from the storage pockets of the interim store, and transferred into the set-down containers, such that they are located in the latter in the order which is to be produced. The set-down containers, which are open at the top, are located along the rectilinear sections of the conveying arrangement, beneath the storage pockets.